Generally, deicing agents can be classified into the following three types. The first type is chlorine-containing deicing agents composed essentially of sodium chloride and calcium chloride, with additional preservative or anti-corrosive agents. The second type is chlorine-free deicing agents composed essentially of an organic salt, such as acetic acid salts. The third type is a mixed deicing agent comprising the chlorine-containing and chlorine-free deicing agents in a particular mixing ratio.
The first and the third type of deicing agents, as described above, are highly corrosive to concrete bridges and roads, and are toxic to surrounding plants, owing to the chlorine ions contained within. As a result, the service life of concrete buildings is shortened and maintenance cost thereof is increased. In contrast, the second type of deicing agents, which contain chlorine-free organic salts, are less corrosive, but are prohibitively expensive, and may cost as much as about ten times as that of the chlorine containing deicing agents. Further, the second type of deicing agents is less effective than the chlorine-containing deicing agents, and thus is difficult to be widely used.
On the other hand, these prior-art deicing agents have short action time and need to be applied several times in order to treat thick snow cover.